[ubuntu] Hard drive only mounted once

Hello! I have a problem with ubuntu 16.04 (it's not a hardware problem because i don't have problems in windows), when i coect a exteal HDD, ubuntu detects and mounts the HDD and i can access to the files without problems, but when i discoect and recoect the HDD, it doesn't appears in nautilus or in gparted, but when i put "lsusb" shows the HDD, but not if i put "sudo fdisk -l" but if i put the "dmesg | tail -n 20" command, this appears:

[ 745.629158] usb 2-1: new high-speed USB device number 6 using xhci_hcd
[ 745.832552] usb 2-1: New USB device found, idVendor=0939, idProduct=0b15
[ 745.832561] usb 2-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 745.832565] usb 2-1: Product: StorE HDD
[ 745.832569] usb 2-1: Manufacturer: Toshiba
[ 745.832572] usb 2-1: SerialNumber: 201209251F55
[ 745.834966] usb-storage 2-1:1.0: USB Mass Storage device detected
[ 745.835183] scsi host4: usb-storage 2-1:1.0
[ 768.135287] usb 2-1: reset high-speed USB device number 6 using xhci_hcd

Can someone help me?